Here’s some further images from December 10, but the other end of the day. These were taken well before culmination, which was good because after midnight the sky, which had been stable for some time because of high pressure, fogged over. Click to see full size.
I had a busy night; seeing was unusually good for this location. Ian Sharp reported exceptional seeing in Sussex as well, but Damian Peach, in a different part of Sussex, reported poor seeing, strangely.
First row are RGB composites. Second row are the same data but presented using an LRGB process, which gives more contrasty results, but worse artefacts. Third row are Infra-red images at 742nm, with Callisto just emerged from occultation in the second one.
Here is an attempt at narrowband imaging with the 10″ f4.8 last night. The light frames total 115 minutes. The palette used is R and L = H alpha, G = 0III, B = SII. Almost all the nebula information is in the H alpha, there’s just a trace of SII emission and little trace of OIII, hence it’s basically red. Processing was in Nebulosity and Photoshop CS4 with Neat Image plugin. (Click to enlarge image)
Here’s my full disk from Saturday. Seeing was not that good.
There’s a lot of scattered light. This is due to the blocking filter. I’ve been finding that my Lunt blocking filters have gradually degraded over time, and are no longer transparent, but “crazed” on the surface of the larger glass component (the one towards the camera or eye). I wonder if anyone else has found this.
I managed to catch an astonishingly fast-moving prominence here. I imaged it for 1 minute runs at 5 minute intervals, but really this was too slow, it was changing so quickly, that shorter runs might have been better. It was moving visibly on screen, and 20 minutes after I first saw it it was dissipating into space. A rough calculation shows it was travelling of the order of 10,000 miles per minute, or 0.1% the speed of light. The frames are about 25% of the Sun’s diameter.
Here’s some images of a rapidly changing nearly-detached prominence on the Sun’s eastern limb.